The Alberta oil sands are considered to be one of the world's largest remaining oil reserves. The oil sands are typically composed of about 70 to about 90 percent by weight mineral solids, including sand and clay, about 1 to about 10 percent by weight water, and a bitumen or oil film, that comprises from trace amounts up to as much as 21 percent by weight. Typically ores containing a lower percentage by weight of bitumen contain a higher percentage by weight of fine mineral solids (“fines”) such as clay and silt.
Unlike conventional oil deposits, the bitumen is extremely viscous and difficult to separate from the water and mineral mixture in which it is found. Generally speaking, the process of separating bitumen from oil sands extracted through surface mining comprises five broad stages: 1) initially, the oil sand is excavated from its location and passed through a comminutor to comminute the chunks of ore into smaller pieces; 2) the comminuted ore is then typically combined with a process fluid, such as hot process water, to aid in liberating the oil (the combined oil sand and process fluid is typically referred to as an “oil sand slurry”, and other agents, such as flotation aids can be added to the slurry); 3) the oil sand slurry is passed through a “conditioning” phase in which the slurry is allowed to mix and dwell for a period to create froth in the mixture; 4) once the slurry has been conditioned, it is typically passed through a series of separators for separating the bitumen froth and the tailings from the oil sand slurry as part of an extraction process; and 5) after the maximum practical amount of bitumen has been separated, the remaining tailings material is typically routed into a tailings pond for separation of the sand and fines from the water, and the resulting bitumen product directed to downstream upgrading and refining operations.
Generally speaking, the process of separating bitumen from oil sands in situ, i.e., within the underground formation, is through Steam-Assisted Gravity Drainage (SAGD), although other processes can be used. SAGD generally involves: 1) injecting steam into an injection well underground, such that the viscosity of bitumen within the formation lowers to a point where the bitumen can flow; 2) extracting a bitumen-containing wellhead product stream through a production well to the surface; 3) processing the bitumen-containing wellhead product stream to recycle water and extract any mineral component; and 4) directing the resulting bitumen product to downstream upgrading operations, and subsequent refining operations depending upon the hydrocarbon product to be produced.
The process of generating bitumen froth from oil sand slurry and then separating the froth typically has inefficiencies, in part caused by a variance in a composition of the oil sand slurry. The process of extracting and processing a bitumen-containing wellhead product stream from an in-situ well head can have inefficiencies related to a variance in a composition of the product stream. It would be advantageous to provide for methods of obtaining composition estimates of the oil sand slurry or bitumen-containing wellhead product stream and resulting product fluids to improve the bitumen recovery performance of the extraction process.